import Clutter from 'gi://Clutter';
import Gio from 'gi://Gio';
import GLib from 'gi://GLib';
import GObject from 'gi://GObject';
import IBus from 'gi://IBus';
import Meta from 'gi://Meta';
import Shell from 'gi://Shell';
import St from 'gi://St';
import * as Gettext from 'gettext';
import * as Signals from '../../misc/signals.js';

import * as IBusManager from '../../misc/ibusManager.js';
import * as KeyboardManager from '../../misc/keyboardManager.js';
import * as Main from '../main.js';
import * as PopupMenu from '../popupMenu.js';
import * as PanelMenu from '../panelMenu.js';
import * as SwitcherPopup from '../switcherPopup.js';
import * as Util from '../../misc/util.js';

export const INPUT_SOURCE_TYPE_XKB = 'xkb';
export const INPUT_SOURCE_TYPE_IBUS = 'ibus';

export const LayoutMenuItem = GObject.registerClass(
class LayoutMenuItem extends PopupMenu.PopupBaseMenuItem {
    _init(displayName, shortName) {
        super._init();

        this.setOrnament(PopupMenu.Ornament.NO_DOT);

        this.label = new St.Label({
            text: displayName,
            x_expand: true,
        });
        this.indicator = new St.Label({text: shortName});
        this.add_child(this.label);
        this.add_child(this.indicator);
        this.label_actor = this.label;
    }
});

export class InputSource extends Signals.EventEmitter {
    constructor(type, id, displayName, shortName, index) {
        super();

        this.type = type;
        this.id = id;
        this.displayName = displayName;
        this._shortName = shortName;
        this.index = index;

        this.properties = null;

        this.xkbId = this._getXkbId();
    }

    get shortName() {
        return this._shortName;
    }

    set shortName(v) {
        this._shortName = v;
        this.emit('changed');
    }

    activate(interactive) {
        this.emit('activate', !!interactive);
    }

    _getXkbId() {
        const engineDesc = IBusManager.getIBusManager().getEngineDesc(this.id);
        if (!engineDesc)
            return this.id;

        if (engineDesc.variant && engineDesc.variant.length > 0)
            return `${engineDesc.layout}+${engineDesc.variant}`;
        else
            return engineDesc.layout;
    }
}

export const InputSourcePopup = GObject.registerClass(
class InputSourcePopup extends SwitcherPopup.SwitcherPopup {
    _init(items, action, actionBackward) {
        super._init(items);

        this._action = action;
        this._actionBackward = actionBackward;

        this._switcherList = new InputSourceSwitcher(this._items);
    }

    _keyPressHandler(keysym, action) {
        if (action === this._action)
            this._select(this._next());
        else if (action === this._actionBackward)
            this._select(this._previous());
        else if (keysym === Clutter.KEY_Left)
            this._select(this._previous());
        else if (keysym === Clutter.KEY_Right)
            this._select(this._next());
        else
            return Clutter.EVENT_PROPAGATE;

        return Clutter.EVENT_STOP;
    }

    _finish() {
        super._finish();

        this._items[this._selectedIndex].activate(true);
    }
});

const InputSourceSwitcher = GObject.registerClass(
class InputSourceSwitcher extends SwitcherPopup.SwitcherList {
    _init(items) {
        super._init(true);

        for (let i = 0; i < items.length; i++)
            this._addIcon(items[i]);
    }

    _addIcon(item) {
        const box = new St.BoxLayout({
            orientation: Clutter.Orientation.VERTICAL,
        });

        const symbol = new St.Bin({
            style_class: 'input-source-switcher-symbol',
            child: new St.Label({
                text: item.shortName,
                x_align: Clutter.ActorAlign.CENTER,
                y_align: Clutter.ActorAlign.CENTER,
            }),
        });
        box.add_child(symbol);

        const text = new St.Label({
            text: item.displayName,
            x_align: Clutter.ActorAlign.CENTER,
        });
        box.add_child(text);

        this.addItem(box, text);
    }
});

class InputSourceSettings extends Signals.EventEmitter {
    constructor() {
        super();

        if (this.constructor === InputSourceSettings)
            throw new TypeError(`Cannot instantiate abstract class ${this.constructor.name}`);
    }

    _emitInputSourcesChanged() {
        this.emit('input-sources-changed');
    }

    _emitKeyboardOptionsChanged() {
        this.emit('keyboard-options-changed');
    }

    _emitKeyboardModelChanged() {
        this.emit('keyboard-model-changed');
    }

    _emitPerWindowChanged() {
        this.emit('per-window-changed');
    }

    get inputSources() {
        return [];
    }

    get mruSources() {
        return [];
    }

    set mruSources(sourcesList) {
        // do nothing
    }

    get keyboardOptions() {
        return [];
    }

    get perWindow() {
        return false;
    }
}

class InputSourceSystemSettings extends InputSourceSettings {
    constructor() {
        super();

        this._BUS_NAME = 'org.freedesktop.locale1';
        this._BUS_PATH = '/org/freedesktop/locale1';
        this._BUS_IFACE = 'org.freedesktop.locale1';
        this._BUS_PROPS_IFACE = 'org.freedesktop.DBus.Properties';

        this._layouts = '';
        this._variants = '';
        this._options = '';
        this._model = '';

        this._reload();

        Gio.DBus.system.signal_subscribe(this._BUS_NAME,
            this._BUS_PROPS_IFACE,
            'PropertiesChanged',
            this._BUS_PATH,
            null,
            Gio.DBusSignalFlags.NONE,
            this._reload.bind(this));
    }

    async _reload() {
        let props;
        try {
            const result = await Gio.DBus.system.call(
                this._BUS_NAME,
                this._BUS_PATH,
                this._BUS_PROPS_IFACE,
                'GetAll',
                new GLib.Variant('(s)', [this._BUS_IFACE]),
                null, Gio.DBusCallFlags.NONE, -1, null);
            [props] = result.deepUnpack();
        } catch {
            log(`Could not get properties from ${this._BUS_NAME}`);
            return;
        }

        const layouts = props['X11Layout'].unpack();
        const variants = props['X11Variant'].unpack();
        const options = props['X11Options'].unpack();
        const model = props['X11Model'].unpack();

        if (layouts !== this._layouts ||
            variants !== this._variants) {
            this._layouts = layouts;
            this._variants = variants;
            this._emitInputSourcesChanged();
        }
        if (options !== this._options) {
            this._options = options;
            this._emitKeyboardOptionsChanged();
        }
        if (model !== this._model) {
            this._model = model;
            this._emitKeyboardModelChanged();
        }
    }

    get inputSources() {
        const sourcesList = [];
        const layouts = this._layouts.split(',');
        const variants = this._variants.split(',');

        for (let i = 0; i < layouts.length && !!layouts[i]; i++) {
            let id = layouts[i];
            if (variants[i])
                id += `+${variants[i]}`;
            sourcesList.push({type: INPUT_SOURCE_TYPE_XKB, id});
        }
        return sourcesList;
    }

    get keyboardOptions() {
        return this._options.split(',');
    }

    get keyboardModel() {
        return this._model;
    }
}

class InputSourceSessionSettings extends InputSourceSettings {
    constructor() {
        super();

        this._DESKTOP_INPUT_SOURCES_SCHEMA = 'org.gnome.desktop.input-sources';
        this._KEY_INPUT_SOURCES = 'sources';
        this._KEY_MRU_SOURCES = 'mru-sources';
        this._KEY_KEYBOARD_OPTIONS = 'xkb-options';
        this._KEY_KEYBOARD_MODEL = 'xkb-model';
        this._KEY_PER_WINDOW = 'per-window';

        this._settings = new Gio.Settings({schema_id: this._DESKTOP_INPUT_SOURCES_SCHEMA});
        this._settings.connect(`changed::${this._KEY_INPUT_SOURCES}`, this._emitInputSourcesChanged.bind(this));
        this._settings.connect(`changed::${this._KEY_KEYBOARD_OPTIONS}`, this._emitKeyboardOptionsChanged.bind(this));
        this._settings.connect(`changed::${this._KEY_KEYBOARD_MODEL}`, this._emitKeyboardModelChanged.bind(this));
        this._settings.connect(`changed::${this._KEY_PER_WINDOW}`, this._emitPerWindowChanged.bind(this));
    }

    _getSourcesList(key) {
        const sourcesList = [];
        const sources = this._settings.get_value(key);
        const nSources = sources.n_children();

        for (let i = 0; i < nSources; i++) {
            const [type, id] = sources.get_child_value(i).deepUnpack();
            sourcesList.push({type, id});
        }
        return sourcesList;
    }

    get inputSources() {
        return this._getSourcesList(this._KEY_INPUT_SOURCES);
    }

    get mruSources() {
        return this._getSourcesList(this._KEY_MRU_SOURCES);
    }

    set mruSources(sourcesList) {
        const sources = GLib.Variant.new('a(ss)', sourcesList);
        this._settings.set_value(this._KEY_MRU_SOURCES, sources);
    }

    get keyboardOptions() {
        return this._settings.get_strv(this._KEY_KEYBOARD_OPTIONS);
    }

    get keyboardModel() {
        return this._settings.get_string(this._KEY_KEYBOARD_MODEL);
    }

    get perWindow() {
        return this._settings.get_boolean(this._KEY_PER_WINDOW);
    }
}

export class InputSourceManager extends Signals.EventEmitter {
    constructor() {
        super();

        // All valid input sources currently in the gsettings
        // KEY_INPUT_SOURCES list indexed by their index there
        this._inputSources = {};
        // All valid input sources currently in the gsettings
        // KEY_INPUT_SOURCES list of type INPUT_SOURCE_TYPE_IBUS
        // indexed by the IBus ID
        this._ibusSources = {};

        this._currentSource = null;

        // All valid input sources currently in the gsettings
        // KEY_INPUT_SOURCES list ordered by most recently used
        this._mruSources = [];
        this._mruSourcesBackup = null;
        this._keybindingAction =
            Main.wm.addKeybinding('switch-input-source',
                new Gio.Settings({schema_id: 'org.gnome.desktop.wm.keybindings'}),
                Meta.KeyBindingFlags.NONE,
                Shell.ActionMode.ALL,
                this._switchInputSource.bind(this));
        this._keybindingActionBackward =
            Main.wm.addKeybinding('switch-input-source-backward',
                new Gio.Settings({schema_id: 'org.gnome.desktop.wm.keybindings'}),
                Meta.KeyBindingFlags.IS_REVERSED,
                Shell.ActionMode.ALL,
                this._switchInputSource.bind(this));
        if (Main.sessionMode.isGreeter)
            this._settings = new InputSourceSystemSettings();
        else
            this._settings = new InputSourceSessionSettings();
        this._settings.connect('input-sources-changed', this._inputSourcesChanged.bind(this));
        this._settings.connect('keyboard-options-changed', this._keyboardOptionsChanged.bind(this));
        this._settings.connect('keyboard-model-changed', this._keyboardModelChanged.bind(this));

        this._xkbInfo = KeyboardManager.getXkbInfo();
        this._keyboardManager = KeyboardManager.getKeyboardManager();

        this._ibusReady = false;
        this._ibusManager = IBusManager.getIBusManager();
        this._ibusManager.connect('ready', this._ibusReadyCallback.bind(this));
        this._ibusManager.connect('properties-registered', this._ibusPropertiesRegistered.bind(this));
        this._ibusManager.connect('property-updated', this._ibusPropertyUpdated.bind(this));
        this._ibusManager.connect('set-content-type', this._ibusSetContentType.bind(this));

        global.display.connect('modifiers-accelerator-activated', this._modifiersSwitcher.bind(this));

        this._sourcesPerWindow = false;
        this._focusWindowNotifyId = 0;
        this._settings.connect('per-window-changed', this._sourcesPerWindowChanged.bind(this));
        this._sourcesPerWindowChanged();
        this._disableIBus = false;
        this._reloading = false;
    }

    reload() {
        this._reloading = true;
        this._keyboardManager.setKeyboardOptions(this._settings.keyboardOptions);
        this._keyboardManager.setKeyboardModel(this._settings.keyboardModel);
        this._inputSourcesChanged();
        this._reloading = false;
    }

    _ibusReadyCallback(im, ready) {
        if (this._ibusReady === ready)
            return;

        this._ibusReady = ready;
        this._mruSources = [];
        this._inputSourcesChanged();
    }

    _modifiersSwitcher() {
        const sourceIndexes = Object.keys(this._inputSources);
        if (sourceIndexes.length === 0) {
            KeyboardManager.releaseKeyboard();
            return true;
        }

        let is = this._currentSource;
        if (!is)
            is = this._inputSources[sourceIndexes[0]];

        let nextIndex = is.index + 1;
        if (nextIndex > sourceIndexes[sourceIndexes.length - 1])
            nextIndex = 0;

        while (!(is = this._inputSources[nextIndex]))
            nextIndex += 1;

        is.activate(true);
        return true;
    }

    _switchInputSource(display, window, event, binding) {
        if (this._mruSources.length < 2)
            return;

        // HACK: Fall back on simple input source switching since we
        // can't show a popup switcher while a GrabHelper grab is in
        // effect without considerable work to consolidate the usage
        // of pushModal/popModal and grabHelper. See
        // https://bugzilla.gnome.org/show_bug.cgi?id=695143 .
        if (Main.actionMode === Shell.ActionMode.POPUP) {
            this._modifiersSwitcher();
            return;
        }

        this._switcherPopup = new InputSourcePopup(
            this._mruSources, this._keybindingAction, this._keybindingActionBackward);
        this._switcherPopup.connect('destroy', () => {
            this._switcherPopup = null;
        });
        if (!this._switcherPopup.show(
            binding.is_reversed(), binding.get_name(), binding.get_mask()))
            this._switcherPopup.fadeAndDestroy();
    }

    _keyboardOptionsChanged() {
        this._keyboardManager.setKeyboardOptions(this._settings.keyboardOptions);
        this._keyboardManager.reapply();
    }

    _keyboardModelChanged() {
        this._keyboardManager.setKeyboardModel(this._settings.keyboardModel);
        this._keyboardManager.reapply();
    }

    _updateMruSettings() {
        // If IBus is not ready we don't have a full picture of all
        // the available sources, so don't update the setting
        if (!this._ibusReady)
            return;

        // If IBus is temporarily disabled, don't update the setting
        if (this._disableIBus)
            return;

        const sourcesList = [];
        for (let i = 0; i < this._mruSources.length; ++i) {
            const source = this._mruSources[i];
            sourcesList.push([source.type, source.id]);
        }

        this._settings.mruSources = sourcesList;
    }

    _currentInputSourceChanged(newSource) {
        let oldSource;
        [oldSource, this._currentSource] = [this._currentSource, newSource];

        this.emit('current-source-changed', oldSource);

        for (let i = 1; i < this._mruSources.length; ++i) {
            if (this._mruSources[i] === newSource) {
                const currentSource = this._mruSources.splice(i, 1);
                this._mruSources = currentSource.concat(this._mruSources);
                break;
            }
        }
        this._changePerWindowSource();
    }

    activateInputSource(is, interactive) {
        // The focus changes during holdKeyboard/releaseKeyboard may trick
        // the client into hiding UI containing the currently focused entry.
        // So holdKeyboard/releaseKeyboard are not called when
        // 'set-content-type' signal is received.
        // E.g. Focusing on a password entry in a popup in Xorg Firefox
        // will emit 'set-content-type' signal.
        // https://gitlab.gnome.org/GNOME/gnome-shell/issues/391
        const holdKeyboard = !this._reloading;
        if (holdKeyboard)
            KeyboardManager.holdKeyboard();
        this._keyboardManager.apply(is.xkbId);

        // All the "xkb:..." IBus engines simply "echo" back symbols,
        // despite their naming implying differently, so we always set
        // one in order for XIM applications to work given that we set
        // XMODIFIERS=@im=ibus in the first place so that they can
        // work without restarting when/if the user adds an IBus input
        // source.
        let engine;
        if (is.type === INPUT_SOURCE_TYPE_IBUS)
            engine = is.id;
        else
            engine = 'xkb:us::eng';

        this._ibusManager.setEngine(engine).then(() => {
            if (holdKeyboard)
                KeyboardManager.releaseKeyboard();
        });

        this._currentInputSourceChanged(is);

        if (interactive)
            this._updateMruSettings();
    }

    _updateMruSources() {
        const sourcesList = [];
        for (const i of Object.keys(this._inputSources).sort((a, b) => a - b))
            sourcesList.push(this._inputSources[i]);

        this._keyboardManager.setUserLayouts(sourcesList.map(x => x.xkbId));

        if (!this._disableIBus && this._mruSourcesBackup) {
            this._mruSources = this._mruSourcesBackup;
            this._mruSourcesBackup = null;
        }

        // Initialize from settings when we have no MRU sources list
        if (this._mruSources.length === 0) {
            const mruSettings = this._settings.mruSources;
            for (let i = 0; i < mruSettings.length; i++) {
                const mruSettingSource = mruSettings[i];
                let mruSource = null;

                for (let j = 0; j < sourcesList.length; j++) {
                    const source = sourcesList[j];
                    if (source.type === mruSettingSource.type &&
                        source.id === mruSettingSource.id) {
                        mruSource = source;
                        break;
                    }
                }

                if (mruSource)
                    this._mruSources.push(mruSource);
            }
        }

        let mruSources = [];
        if (this._mruSources.length > 1) {
            for (let i = 0; i < this._mruSources.length; i++) {
                for (let j = 0; j < sourcesList.length; j++) {
                    if (this._mruSources[i].type === sourcesList[j].type &&
                        this._mruSources[i].id === sourcesList[j].id) {
                        mruSources = mruSources.concat(sourcesList.splice(j, 1));
                        break;
                    }
                }
            }
        }

        this._mruSources = mruSources.concat(sourcesList);
    }

    _inputSourcesChanged() {
        const sources = this._settings.inputSources;
        const nSources = sources.length;

        this._currentSource = null;
        this._inputSources = {};
        this._ibusSources = {};

        const infosList = [];
        for (let i = 0; i < nSources; i++) {
            let displayName;
            let shortName;
            const type = sources[i].type;
            const id = sources[i].id;
            let exists = false;

            if (type === INPUT_SOURCE_TYPE_XKB) {
                [exists, displayName, shortName] =
                    this._xkbInfo.get_layout_info(id);
            } else if (type === INPUT_SOURCE_TYPE_IBUS) {
                if (this._disableIBus)
                    continue;
                const engineDesc = this._ibusManager.getEngineDesc(id);
                if (engineDesc) {
                    const language = IBus.get_language_name(engineDesc.get_language());
                    let longName = engineDesc.get_longname();
                    const textdomain = engineDesc.get_textdomain();
                    if (textdomain !== '')
                        longName = Gettext.dgettext(textdomain, longName);
                    exists = true;
                    displayName = `${language} (${longName})`;
                    shortName = this._makeEngineShortName(engineDesc);
                }
            }

            if (exists)
                infosList.push({type, id, displayName, shortName});
        }

        if (infosList.length === 0) {
            const type = INPUT_SOURCE_TYPE_XKB;
            const id = KeyboardManager.DEFAULT_LAYOUT;
            const [, displayName, shortName] = this._xkbInfo.get_layout_info(id);
            infosList.push({type, id, displayName, shortName});
        }

        const inputSourcesByShortName = {};
        for (let i = 0; i < infosList.length; i++) {
            const is = new InputSource(infosList[i].type,
                infosList[i].id,
                infosList[i].displayName,
                infosList[i].shortName,
                i);
            is.connect('activate', this.activateInputSource.bind(this));

            if (!(is.shortName in inputSourcesByShortName))
                inputSourcesByShortName[is.shortName] = [];
            inputSourcesByShortName[is.shortName].push(is);

            this._inputSources[is.index] = is;

            if (is.type === INPUT_SOURCE_TYPE_IBUS)
                this._ibusSources[is.id] = is;
        }

        for (const i in this._inputSources) {
            const is = this._inputSources[i];
            if (inputSourcesByShortName[is.shortName].length > 1) {
                const sub = inputSourcesByShortName[is.shortName].indexOf(is) + 1;
                is.shortName += String.fromCharCode(0x2080 + sub);
            }
        }

        this.emit('sources-changed');

        this._updateMruSources();

        if (this._mruSources.length > 0)
            this._mruSources[0].activate(false);

        // All ibus engines are preloaded here to reduce the launching time
        // when users switch the input sources.
        this._ibusManager.preloadEngines(Object.keys(this._ibusSources));
    }

    _makeEngineShortName(engineDesc) {
        const symbol = engineDesc.get_symbol();
        if (symbol && symbol[0])
            return symbol;

        const langCode = engineDesc.get_language().split('_', 1)[0];
        if (langCode.length === 2 || langCode.length === 3)
            return langCode.toLowerCase();

        return String.fromCharCode(0x2328); // keyboard glyph
    }

    _ibusPropertiesRegistered(im, engineName, props) {
        const source = this._ibusSources[engineName];
        if (!source)
            return;

        source.properties = props;

        if (source === this._currentSource)
            this.emit('current-source-changed', null);
    }

    _ibusPropertyUpdated(im, engineName, prop) {
        const source = this._ibusSources[engineName];
        if (!source)
            return;

        if (this._updateSubProperty(source.properties, prop) &&
            source === this._currentSource)
            this.emit('current-source-changed', null);
    }

    _updateSubProperty(props, prop) {
        if (!props)
            return false;

        let p;
        for (let i = 0; (p = props.get(i)) != null; ++i) {
            if (p.get_key() === prop.get_key() && p.get_prop_type() === prop.get_prop_type()) {
                p.update(prop);
                return true;
            } else if (p.get_prop_type() === IBus.PropType.MENU) {
                if (this._updateSubProperty(p.get_sub_props(), prop))
                    return true;
            }
        }
        return false;
    }

    _ibusSetContentType(im, purpose, _hints) {
        // Avoid purpose changes while the switcher popup is shown, likely due to
        // the focus change caused by the switcher popup causing this purpose change.
        if (this._switcherPopup)
            return;
        if (purpose === IBus.InputPurpose.PASSWORD) {
            if (Object.keys(this._inputSources).length === Object.keys(this._ibusSources).length)
                return;

            if (this._disableIBus)
                return;
            this._disableIBus = true;
            this._mruSourcesBackup = this._mruSources.slice();
        } else {
            if (!this._disableIBus)
                return;
            this._disableIBus = false;
        }
        this.reload();
    }

    _getNewInputSource(current) {
        const sourceIndexes = Object.keys(this._inputSources);
        if (sourceIndexes.length === 0)
            return null;

        if (current) {
            for (const i in this._inputSources) {
                const is = this._inputSources[i];
                if (is.type === current.type &&
                    is.id === current.id)
                    return is;
            }
        }

        return this._inputSources[sourceIndexes[0]];
    }

    _getCurrentWindow() {
        if (Main.overview.visible)
            return Main.overview;
        else
            return global.display.focus_window;
    }

    _setPerWindowInputSource() {
        const window = this._getCurrentWindow();
        if (!window)
            return;

        if (!window._inputSources ||
            window._inputSources !== this._inputSources) {
            window._inputSources = this._inputSources;
            window._currentSource = this._getNewInputSource(window._currentSource);
        }

        if (window._currentSource)
            window._currentSource.activate(false);
    }

    _sourcesPerWindowChanged() {
        this._sourcesPerWindow = this._settings.perWindow;

        if (this._sourcesPerWindow && this._focusWindowNotifyId === 0) {
            this._focusWindowNotifyId = global.display.connect('notify::focus-window',
                this._setPerWindowInputSource.bind(this));
            Main.overview.connectObject(
                'showing', this._setPerWindowInputSource.bind(this),
                'hidden', this._setPerWindowInputSource.bind(this), this);
        } else if (!this._sourcesPerWindow && this._focusWindowNotifyId !== 0) {
            global.display.disconnect(this._focusWindowNotifyId);
            this._focusWindowNotifyId = 0;
            Main.overview.disconnectObject(this);

            const windows = global.get_window_actors().map(w => w.meta_window);
            for (let i = 0; i < windows.length; ++i) {
                delete windows[i]._inputSources;
                delete windows[i]._currentSource;
            }
            delete Main.overview._inputSources;
            delete Main.overview._currentSource;
        }
    }

    _changePerWindowSource() {
        if (!this._sourcesPerWindow)
            return;

        const window = this._getCurrentWindow();
        if (!window)
            return;

        window._inputSources = this._inputSources;
        window._currentSource = this._currentSource;
    }

    get currentSource() {
        return this._currentSource;
    }

    get inputSources() {
        return this._inputSources;
    }

    get keyboardManager() {
        return this._keyboardManager;
    }
}

let _inputSourceManager = null;

/**
 * @returns {InputSourceManager}
 */
export function getInputSourceManager() {
    if (_inputSourceManager == null)
        _inputSourceManager = new InputSourceManager();
    return _inputSourceManager;
}

const InputSourceIndicatorContainer = GObject.registerClass(
class InputSourceIndicatorContainer extends St.Widget {
    vfunc_get_preferred_width(forHeight) {
        // Here, and in vfunc_get_preferred_height, we need to query
        // for the height of all children, but we ignore the results
        // for those we don't actually display.
        return this.get_children().reduce((maxWidth, child) => {
            const width = child.get_preferred_width(forHeight);
            return [
                Math.max(maxWidth[0], width[0]),
                Math.max(maxWidth[1], width[1]),
            ];
        }, [0, 0]);
    }

    vfunc_get_preferred_height(forWidth) {
        return this.get_children().reduce((maxHeight, child) => {
            const height = child.get_preferred_height(forWidth);
            return [
                Math.max(maxHeight[0], height[0]),
                Math.max(maxHeight[1], height[1]),
            ];
        }, [0, 0]);
    }

    vfunc_allocate(box) {
        this.set_allocation(box);

        // translate box to (0, 0)
        box.x2 -= box.x1;
        box.x1 = 0;
        box.y2 -= box.y1;
        box.y1 = 0;

        this.get_children().forEach(c => {
            c.allocate_align_fill(box, 0.5, 0.5, false, false);
        });
    }
});

export const InputSourceIndicator = GObject.registerClass(
class InputSourceIndicator extends PanelMenu.Button {
    _init() {
        super._init(0.5, _('Keyboard'));

        this.connect('destroy', this._onDestroy.bind(this));

        this._menuItems = {};
        this._indicatorLabels = {};

        this._container = new InputSourceIndicatorContainer({style_class: 'system-status-icon'});
        this.add_child(this._container);

        this._propSeparator = new PopupMenu.PopupSeparatorMenuItem();
        this.menu.addMenuItem(this._propSeparator);
        this._propSection = new PopupMenu.PopupMenuSection();
        this.menu.addMenuItem(this._propSection);
        this._propSection.actor.hide();

        this.menu.addMenuItem(new PopupMenu.PopupSeparatorMenuItem());
        this._showLayoutItem = this.menu.addAction(_('Show Keyboard Layout'), this._showLayout.bind(this));
        this.menu.addSettingsAction(_('Keyboard Settings'),
            'gnome-keyboard-panel.desktop');

        Main.sessionMode.connect('updated', this._sessionUpdated.bind(this));
        this._sessionUpdated();

        this._inputSourceManager = getInputSourceManager();
        this._inputSourceManager.connectObject(
            'sources-changed', this._sourcesChanged.bind(this),
            'current-source-changed', this._currentSourceChanged.bind(this), this);
        this._inputSourceManager.reload();
    }

    _onDestroy() {
        this._inputSourceManager = null;
    }

    _sessionUpdated() {
        // re-using "allowSettings" for the keyboard layout is a bit shady,
        // but at least for now it is used as "allow popping up windows
        // from shell menus"; we can always add a separate sessionMode
        // option if need arises.
        this._showLayoutItem.visible = Main.sessionMode.allowSettings;
    }

    _sourcesChanged() {
        for (const i in this._menuItems)
            this._menuItems[i].destroy();
        for (const i in this._indicatorLabels)
            this._indicatorLabels[i].destroy();

        this._menuItems = {};
        this._indicatorLabels = {};

        let menuIndex = 0;
        for (const i in this._inputSourceManager.inputSources) {
            const is = this._inputSourceManager.inputSources[i];

            const menuItem = new LayoutMenuItem(is.displayName, is.shortName);
            menuItem.connect('activate', () => is.activate(true));

            const indicatorLabel = new St.Label({
                text: is.shortName,
                visible: false,
            });

            this._menuItems[i] = menuItem;
            this._indicatorLabels[i] = indicatorLabel;
            is.connect('changed', () => {
                menuItem.indicator.set_text(is.shortName);
                indicatorLabel.set_text(is.shortName);
            });

            this.menu.addMenuItem(menuItem, menuIndex++);
            this._container.add_child(indicatorLabel);
        }
    }

    _currentSourceChanged(manager, oldSource) {
        const nVisibleSources = Object.keys(this._inputSourceManager.inputSources).length;
        const newSource = this._inputSourceManager.currentSource;

        if (oldSource) {
            this._menuItems[oldSource.index].setOrnament(PopupMenu.Ornament.NO_DOT);
            this._indicatorLabels[oldSource.index].hide();
        }

        if (!newSource || (nVisibleSources < 2 && !newSource.properties)) {
            // This source index might be invalid if we weren't able
            // to build a menu item for it, so we hide ourselves since
            // we can't fix it here. *shrug*

            // We also hide if we have only one visible source unless
            // it's an IBus source with properties.
            this.menu.close();
            this.hide();
            return;
        }

        this.show();

        this._buildPropSection(newSource.properties);

        this._menuItems[newSource.index].setOrnament(PopupMenu.Ornament.DOT);
        this._indicatorLabels[newSource.index].show();
    }

    _buildPropSection(properties) {
        this._propSeparator.hide();
        this._propSection.actor.hide();
        this._propSection.removeAll();

        this._buildPropSubMenu(this._propSection, properties);

        if (!this._propSection.isEmpty()) {
            this._propSection.actor.show();
            this._propSeparator.show();
        }
    }

    _getGraphemeClusters(text = '') {
        const segmenter = new Intl.Segmenter(undefined, {granularity: 'grapheme'});
        const segments = [...segmenter.segment(text)].map(o => o.segment);
        return segments;
    }

    _buildPropSubMenu(menu, props) {
        if (!props)
            return;

        const ibusManager = IBusManager.getIBusManager();
        const radioGroup = [];
        let p;
        for (let i = 0; (p = props.get(i)) != null; ++i) {
            const prop = p;

            if (!prop.get_visible())
                continue;

            if (prop.get_key() === 'InputMode') {
                let text;
                if (prop.get_symbol)
                    text = prop.get_symbol().get_text();
                else
                    text = prop.get_label().get_text();

                const currentSource = this._inputSourceManager.currentSource;
                if (currentSource) {
                    const indicatorLabel = this._indicatorLabels[currentSource.index];
                    const graphemeClusters = this._getGraphemeClusters(text);
                    if (graphemeClusters.length > 0 && graphemeClusters.length < 3)
                        indicatorLabel.set_text(text);
                }
            }

            let item;
            const type = prop.get_prop_type();
            switch (type) {
            case IBus.PropType.MENU:
                item = new PopupMenu.PopupSubMenuMenuItem(prop.get_label().get_text());
                this._buildPropSubMenu(item.menu, prop.get_sub_props());
                break;

            case IBus.PropType.RADIO:
                item = new PopupMenu.PopupMenuItem(prop.get_label().get_text());
                item.prop = prop;
                radioGroup.push(item);
                item.radioGroup = radioGroup;
                item.setOrnament(prop.get_state() === IBus.PropState.CHECKED
                    ? PopupMenu.Ornament.DOT : PopupMenu.Ornament.NO_DOT);
                item.connect('activate', () => {
                    if (item.prop.get_state() === IBus.PropState.CHECKED)
                        return;

                    const group = item.radioGroup;
                    for (let j = 0; j < group.length; ++j) {
                        if (group[j] === item) {
                            item.setOrnament(PopupMenu.Ornament.DOT);
                            item.prop.set_state(IBus.PropState.CHECKED);
                            ibusManager.activateProperty(
                                item.prop.get_key(), IBus.PropState.CHECKED);
                        } else {
                            group[j].setOrnament(PopupMenu.Ornament.NO_DOT);
                            group[j].prop.set_state(IBus.PropState.UNCHECKED);
                            ibusManager.activateProperty(
                                group[j].prop.get_key(), IBus.PropState.UNCHECKED);
                        }
                    }
                });
                break;

            case IBus.PropType.TOGGLE:
                item = new PopupMenu.PopupSwitchMenuItem(prop.get_label().get_text(), prop.get_state() === IBus.PropState.CHECKED);
                item.prop = prop;
                item.connect('toggled', () => {
                    if (item.state) {
                        item.prop.set_state(IBus.PropState.CHECKED);
                        ibusManager.activateProperty(
                            item.prop.get_key(), IBus.PropState.CHECKED);
                    } else {
                        item.prop.set_state(IBus.PropState.UNCHECKED);
                        ibusManager.activateProperty(
                            item.prop.get_key(), IBus.PropState.UNCHECKED);
                    }
                });
                break;

            case IBus.PropType.NORMAL:
                item = new PopupMenu.PopupMenuItem(prop.get_label().get_text());
                item.prop = prop;
                item.connect('activate', () => {
                    ibusManager.activateProperty(
                        item.prop.get_key(), item.prop.get_state());
                });
                break;

            case IBus.PropType.SEPARATOR:
                item = new PopupMenu.PopupSeparatorMenuItem();
                break;

            default:
                log(`IBus property ${prop.get_key()} has invalid type ${type}`);
                continue;
            }

            item.setSensitive(prop.get_sensitive());
            menu.addMenuItem(item);
        }
    }

    _showLayout() {
        Main.overview.hide();

        Util.spawn(['tecla']);
    }
});
